In vehicles having conventional disk brakes, in the unbraked operating state, i.e., when the brake pedal is not actuated, energy losses in the form of a residual braking torque often occur, since the brake pads rub against the brake disk. Such rubbing may be caused, for example, by disk knocking and/or in many cases by incorrect pad return and the correct clearing not being maintained.
In order to save energy, disk brakes have therefore been developed in which the brake in the unbraked state is in a so-called zero drag position, so that no rubbing occurs between the brake pads and the brake disk. An appropriately designed brake caliper is often referred to as a zero drag caliper.
A disadvantage with such braking systems, however, is that after the brake pedal is released the brake pads often retract a long way from the brake disk, so that when the brake actuating element is actuated there is increased free or dead travel compared to conventional braking systems. Such additional free or dead travel, however, is undesirable and should therefore be avoided or compensated for. In this connection it should be pointed out that such increased free or dead travel may also result from the design of the system irrespective of whether or not zero drag calipers are used.
Compensation for such undesirable free or dead travel has previously been possible only through the use of so-called non-muscular-energy braking systems, in which the energy necessary for generating the braking force is generated by one or multiple energy supply devices, but not by the physical effort of the driver.